This application relates to a simple manual control system, for providing control to a fluid flow apparatus which typically performs a relatively complex series of fluid switching functions through multiple flow paths. Additionally, the control system of this invention can simultaneously control the electrical functions of the same apparatus, in correlation with the fluid flow functions, from a single control knob.
The requirements of greater efficiency and cost reduction throughout all of technology, and specifically in the medical field, are resulting in the development of the relatively automated apparatus such as for the processing of blood or blood components, or for analysis of medical or other fluids. Such apparatus may be used in hemodialysis, blood oxygenation, or blood collection and component separation, including plasmapheresis.
In Sikula U.S. Pat. No. 2,986,168, a control valve is shown for controlling fluid flow through a pair of valving elements as disposed in a single body.
In Gates U.S. Pat. No. 1,427,455, cam operated valves control multiple flexible flow passages by compressing them to close, and by releasing them to open.
Bloch U.S. Pat. No. 1,690,767 discloses another type of delivery valve in which cams on a rotatable member open and close a pair of valves.
However, a need remains for a control system which is capable of separately and independently controlling the flow from a single control member through multiple flow paths, while at the same time optionally providing correlated electrical controls. Furthermore, in accordance with this invention, a control member may be mounted on a door or other separable member of the apparatus, with means being provided so that the connection of the control knob to the controlled elements may be disconnected and reconnected in a manner which does not permit disruption of the correlation of the position of the control knob with the controlled elements.